Friedel-like Oscillations from Interstitial Iron in Superconducting Fe$_{1+y}$Te$_{0.62}$Se$_{0.38}$

ORAL

Abstract

Using polarized and unpolarized neutron scattering we show that interstitial Fe in superconducting Fe$_{1+y}$Te$_{1-x}$Se$_x$ induces a magnetic Friedel-like oscillation that diffracts at ${\bf Q}_{\perp}=(\frac{1}{2}0)$ and involves $>$50 neighboring Fe sites. The interstitial $>2$~$\mu_B$ moment is surrounded by compensating ferromagnetic four spin clusters that may seed double stripe ordering in Fe$_{1+y}$Te. A semi-metallic 5-band model with $(\frac{1}{2}\frac{1}{2})$ Fermi surface nesting and four fold symmetric super-exchange between interstitial Fe and two in-plane nearest neighbors largely accounts for the observed diffraction.

*Work at IQM was supported by DoE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-FG02-08ER46544

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Authors

  • Vivek Thampy

    • Johns Hopkins University

  • J. Kang

    • Institute for Quantum Matter, Johns Hopkins University

  • J.A. Rodriguez-Rivera

    • NIST Center for Neutron Research

  • W. Bao

    • Department of Physics, Renmin University of China

  • A.T. Savici

    • NSSD, Oak Ridge National Laboratory

  • J. Hu

    • Department of Physics, Tulane University

  • T.J. Liu

    • Department of Physics, Tulane University

  • B. Qian

    • Department of Physics, Tulane University

  • D. Fobes

    • Department of Physics, Tulane University

  • Z.Q. Mao

    • Department of Physics, Tulane University

  • C.B. Fu

    • Department of Physics, Indiana University

  • W.C. Chen

    • Department of Materials Science and Engineering, University of Maryland

  • Q. Ye

    • NSSD, Oak Ridge National Laboratory

  • R.W. Erwin

    • NIST Center for Neutron Research

  • T.R. Gentile

    • National Institute of Standards and Technology

  • Z. Tesanovic

    • Institute for Quantum Matter, Johns Hopkins University

  • C. Broholm

    • Institute for Quantum Matter, Johns Hopkins University